The study had no idea why, and honestly there's so much diversity between the Tri-Cities, Vancouver, Spokane and Seattle areas that it'd be hard to come up with one, but the poll analysts mumbled something about construction projects being a possible cause.

On average, drivers confessed to engaging in about two acts of aggressive driving per month (cutting someone off on purpose, tailgating them, honking/gesturing, etc.). They estimated they were extra polite about 8-9 times per month. Generally speaking they felt other drivers were courteous, especially compared to other areas of the country, even though they estimated other drivers commit around 5 aggressive acts per month.

Oregon was slightly more polite, which doesn't surprise anyone.

Millennials admitted to almost three aggressive acts per month -- up from two in 2015.

I've personally encountered the most aggressive drivers on 240 passing Columbia Park and on Columbia Center Blvd. Everywhere else people are chill, but maybe on those stretches they're really "hangry" for their Carl's Jr or something.